LESSON 1 · Water: Earth's Scarcest Treasure
The Three Percent Problem
Water covers seventy-one percent of Earth's surface, but only three percent is freshwater. Of that three percent, two-thirds is locked in glaciers and ice caps. The freshwater available for human use — in rivers, lakes, and accessible groundwater — represents less than one percent of all water on Earth.

The crisis is not about total water — Earth has the same amount it always had. It is about distribution, timing, and quality. Water is abundant where few people live and scarce where billions concentrate, creating a geography of thirst that climate change is rapidly worsening.